Aluminum nitride. Preparation methods (Review)

Thermodynamic Analysis of a New Gas-Phase Method of Obtaining High-Purity Aluminum Nitride

“…Thermodynamic Analysis of a New Gas-Phase Method of Obtaining High-Purity Aluminum Nitride 99 Two parameters determine the equilibrium conditions for the direct nitriding of aluminum in the gaseous state in accordance with reaction (4). The values of the equilibrium constants K e = P N2 ·P Al will depend either on the temperature and the total pressure of the gas phase for a given composition of gas phase or on temperature and gas-phase composition when total pressure in the reaction zone is constant.…”

“…For reaction (4), the equilibrium conditions are described by the equation K e = 1/(P(N 2 )·P 2 (Al) and depend on two parameters.…”

“…(1) - (4) shows that a change in temperature, the composition of the gas phase, or total pressure or a change in these quantities in some combination can either stimulate or inhibit the formation of the reaction products, i.e. these parameters ultimately affect the character of the processes which take place in the production of AlN by the gas-phase mechanism.…”

“…The presence of even a small amount of oxygen in the material significantly reduces its thermal conductivity (the most important property of aluminum nitride) due to the formation of oxides and oxynitrides on the surface of the grains. The articles [4,5] presented a detailed survey of the methods used to obtain aluminum nitride and discussed each method's positive and negative aspects. For example, powders obtained by industrial methods -carbothermic reduction and direct nitriding -are not very pure.…”

Graphite Behavior During a gas Phase Method for Aluminum Nitride Preparation

“…However no method exists providing industrial preparation of high-purity aluminium nitride [4,5]. A number of works [4 -7] consider new promising gas-phase synthesis of aluminium nitride.…”